This proposal seeks support for the 21st Gordon Research Conference on Bacterial Cell Surfaces, which will be held June 22-27, 2014 at Mount Snow Resort, West Dover, VT. The meeting focuses on the biogenesis, structure and function of bacterial envelopes and surfaces, including bacterial membranes, cell walls, and surface appendages and polymers. This conference presents a diverse program in topics, model systems, and approaches combining biochemistry, molecular genetics, structural biology, biophysics, imaging and modeling. There will be 9 sessions on topics related to 1) cell wall biogenesis, 2) surface polymers, exopolysaccharides and their secretion, 3) cell compartmentalization and protein localization, 4) motility, surface structures and contact-dependent intercellular activities, 5) protein secretion, 6) cell division and morphogenesis, 7) envelope stress responses, 8) inner and outer membrane biogenesis, and 9) transport across the cell envelope. The objectives of this conference are to: 1) present the latest and most exciting research in these areas by bringing together a diverse group of scientists with respect to approaches, expertise, experimental model, and seniority; 2) generate new ideas and stimulate intellectual exchange between this diverse group of investigators; and 3) provide opportunities for graduate students and postdoctoral fellows to present their work in short-talk or poster format and to interact with leaders in the field. The traditional format of the Gordon Research Conferences, with programmed discussion sessions and opportunities for informal gatherings in the afternoons and evenings, conveys a collegial atmosphere where interactions between attendees are easily attained. Although the science presented is basic in nature, the topics of this multifaceted conference are of practical interest to the biomedical community in the areas of pathogenesis, antibiotic action and resistance, and host-microbe interactions, as many of these phenomena involve processes at the level of membranes, cell walls and cell surface. This conference will thus provide a platform for future developments of vaccine and antibacterial strategies.